Wolverine, Best There Is

Unrivaled Lethality — Double all damage Wolverine would deal.
At the beginning of each end step, if Wolverine dealt damage to another creature this turn, put a +1/+1 counter on him.
{1}{G}: Regenerate Wolverine. (The next time he would be destroyed this turn, instead tap him, remove him from combat, and heal all damage on him.)

Mage Slayer

Whenever equipped creature attacks, it deals damage equal to its power to the player or planeswalker it's attacking.
Equip {3}

The Ozolith

Whenever a creature you control leaves the battlefield, if it had counters on it, put those counters on The Ozolith.
At the beginning of combat on your turn, if The Ozolith has counters on it, you may move all counters from The Ozolith onto target creature.

Manglehorn

When this creature enters, you may destroy target artifact.
Artifacts your opponents control enter tapped.

Berserk

Cast this spell only before the combat damage step.
Target creature gains trample and gets +X/+0 until end of turn, where X is its power. At the beginning of the next end step, destroy that creature if it attacked this turn.

Vexing Shusher

This spell can't be countered.
{R/G}: Target spell can't be countered.

Rhythm of the Wild

Creature spells you control can't be countered.
Nontoken creatures you control have riot. (They enter with your choice of a +1/+1 counter or haste.)